Polyimides arc useful as components which require excellent thermal, electrical and/or mechanical properties. For general discussion of polyimides preparation, characterization and applications see Polyimides, Synthesis, Characterization and Applications, K. L. Mittal, ed Plenum, N.Y. 1984.
Polyimides based on pyromellitic dianhydride and various organic diamines are disclosed in U.S. Pat. No. 4,485,140 to Gannett et al (E. I. DuPont de Nemours and Co.).
Polyimides based on diamines such as 2,2'-di-(p-aminophenyloxy)diphenyl and various dianhydrides are disclosed in U.S. Pat. No. 4,239,880 to Danns (Ciba-Geigy Co.).
Harris et al. in U.S. patent application 07/315,327, has disclosed the preparation of soluble polyimides based on polyphenylated diamines. The polyimides taught in this reference are typically rod like polyimides and possess little if any thermoplastic properties.
None of the above patents teaches the increased solubility of resultant polyimides which are derived from substituted biphenyl dianhydrides.